So I tried the Sony Alpha DSLR-A580 – the less famous cousin of the Sony Alpha SLT-A55V. Its sibling, the A560, was delayed to 2011. It has a real nice grip to it, with a nice embossed mode dial.
The firmware is interestingly, Version 1.11.
In the menu you can choose Contrast Detect AF or Phase Detect AF to be used in Focus Check Live View.
In the A550, it was called Manual Focus Check Live View. Now that the camera can focus in main-sensor Live View (which is what Manual Focus Check Live View is, really) it had to change its name.
Phase Detect requires that the mirror drop back down so it can direct light to the Phase Detect AF sensors in the bottom of the camera.
Contrast Detect just uses the main sensor Live View to focus, albeit a lot, lot slower. At least the mirror does not move.
I recorded a video to show this.
Yes, there is no autofocus in video! You cannot manually focus and get a focus confirmation either! (The A55 and its sibling, the A33, show focus confirmation because its phase detect AF sensors are still seeing the view.)
A lot has been improved or brought back, but in essence it’s still an old concept, based on the SLR idea. Translucent mirrors like on the SLT-A33 and SLT-A55, however, are an interesting way to tackle the limitations of the SLR focusing/viewing design!